The effectiveness of radiotherapy in preventing disease recurrence after breast cancer surgery

• DOI: 10.1016/j.suronc.2022.101709
• Publication Date: 2022-02-02T01:22:47Z
• Authors: Felipe Andrés Cor...; Eduarda da Costa ...; Camila Piqui Nasc...; Lara de Andrade M...; Mateus Bringel Ol...; Patrícia Ferreira...; Rafael Mathias An...; Rogério Agenor de...; Marcelo José Barb...
• Keywords: 03 medical and health sciences; 0302 clinical medicine; Humans; Margins of Excision; Breast Neoplasms; Female; Radiotherapy, Adjuvant; Neoplasm Recurrence, Local; Neoplasm Staging; Retrospective Studies; 3. Good health

The locoregional management of breast cancer has a critical impact on prognosis. This study aimed to analyze the effectiveness of radiotherapy against the deleterious effect of positive surgical margins on disease outcomes.Retrospective, single-center study enrolled 721 breast cancer patients with a median follow-up of approximately 64.50 months (3.67-247.40). Analyses were performed considering the end of adjuvant therapy, except endocrine therapy. Kaplan-Meier and Cox regression were performed to obtain the predictive value of treatments.The minimally adequate radiotherapy (≥45 cGy) was associated with improved outcomes in breast cancer patients compared to inadequate radiotherapy (<45 cGy/no) by controlling locoregional relapses and distant metastasis. In patients with positive surgical margins (n = 53), radiotherapy was associated with an approximate decrease of 90% in locoregional relapse risk [adjusted HR: 0.108 (0.012-0.932), p = 0.043]. Radiotherapy did not alter the adverse effect of positive surgical margins, especially in patients with a higher risk of poorly differentiated tumors (n = 146), presence of lymphovascular invasion (n = 163), and triple-negative subtype (n = 113). Notwithstanding, radiotherapy was associated with respective decreases of distant metastasis risk of 75.2% [adjusted HR: 0.248 (0.081-0.762), p = 0.015] and 67.8% [adjusted HR: 0.322 (0.101-1.029), p = 0.056] in patients with triple-negative tumors or with lymphovascular invasion.Adequate radiotherapy is associated with better outcomes in breast cancer. Despite improving locoregional relapse-free survival, radiotherapy does not ablate positive surgical margins, a factor of poorer prognosis that prevails mainly in patients with factors of higher relapse risk.